How to Measure BSP Pipe Fittings | Anglo Stainless

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Stainless Steel BSP Male Adaptor

How to Measure BSP Pipe Fittings

British Standard Pipe threads, or BSP threads, are some of the most popular and commonly used threads in the world today. They are made in two varieties – parallel (BSPP) and tapered (BSPT).

If you’re trying to identify or replace a coupling or fitting, you will need to know how to measure your BSP fittings. This may seem a difficult process, but we’ve prepared a simple guide to tell you all you need to know about how to measure both BSPP and BSPT fittings.

Measuring BSPP fittings

Identifying the specifications of a BSPP fitting is a fairly straightforward process. First of all, you will need to measure the outer diameter of the thread in inches, before subtracting ¼ inch from the measurement you took to calculate the thread size. For instance, a thread with an outer diameter of 2 ¼ inches would have a thread size of 2 inches.

Next, count how many threads per inch to make sure it’s a BSP fitting. Once you have this information, you can use it together with the thread size and cross-reference it using a table like the one here to find the size and specifications of your fitting.

Measuring BSPT fittings

The process for measuring BSPT fittings is largely identical to the one described above. However, because BSPT fittings are tapered, their outer diameter varies and so the formula is not as reliable. Rather than measuring the outer diameter, it’s better to instead determine the fitting’s inner diameter by taking a calliper reading from inside its bore and then referencing the table as before.

Anglo Stainless provide clients all around the world with a comprehensive range of quality stainless steel pipe fittings and flanges. To find out more, please get in touch by calling 01924 430044 or emailing us at

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